Jet Ventilation: high or low frequency

Microlaryngeal surgery

Jet Ventilation: HFJV or LFJV

References

Abnormal Laryngeal Function. (2006).

Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy. (2015). Retrieved from

Miller, R. D., & Eriksson, L. I. (2010). Miller's anesthesia. Philadelphia: Churchill Livingstone Elsevier.

OpenAnesthesia. (2012).

Pillow, J. J. (2005, March). High-frequency oscillatory ventilation: Mechanisms of gas exchange and lung mechanics.

Sandber W, Uman RD, and Ehrenfield JM. The MGH Textbook of Anesthetic Equipment. Philadephia, PA: Elsevier; 2011: 120

Simon, B. A., Kaczka, D. W., Bankier, A. A., & Parraga, G. (2012, August 15). What can computed tomography and magnetic resonance imaging tell us about ventilation?

Sue, F. S., Li, R. P., & Liu, G. P. (2014). A novel technique for the insertion of a hunsaker mon-jet catheter. Retrieved from

Themes, U. (2016, May 23). Otolaryngology-Head and Neck Surgery.

David Budenbender, SRNA

Wolford College

Graduation June 2017

d.budenbender@gmail.com

Clinical case:

Application for jet ventilation

• Vocal cord malady requiring optimization of surgical field access
• Excellent visualization of an unobstructed access to vocal folds
• Often requiring long surgical times
• Procedure requiring GET with muscle relaxation
• Requirement for apnic ventilation

• 58 year old male,73 inches (185 cm), 95 kg (209 pounds), 27.8 BMI, ASA III, Mallampati 2
• Patient has been seen by surgeon for 2 years c/o progressively worsening horseness, HTN, EF 43%, atrial fibrillation (case canceled and referred to cardiologist 3 months ago), 2nd attempt to have microlaryngoscopy
• CO2 Laser used to remove vocal cord polyp, paralyzed with rocuronium
• Maintenance with 30psi 4-6x minute and O2 saturation maintained at 99% for duration of case (1 1/2 hours)
• Full reversal, smooth emergence, maintained O2 saturation for 10-15 minutes
• Desaturation, re-intubation by ENT surgeon, called for transport from surgery center to hospital

Figure 38- 12

("Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

Figure 9 Vocal Cord Polyps

("Abnormal Laryngeal Function," 2006)

Limitations:

Preoperative evaluation:

Subtly appearance on the surface

Hoarseness

Difficult phonating words properly

Drooling

Dysphagia

Stridor (inspiratory/expiratory); Inspiratory most worrisome = reduction of airway diameter

Limitations:

* Misalignment of the suspension laryngoscope to the glottic inlet ~resulting in poor ventilation & risk of gastric distention with entrained air

* Blood, smoke, & debris are blown into the distal trachea

* Considerable vibration and movement of vocal cords occurs, which may require ventilation to be stopped while operating

* Inability to monitor end-tidal carbon dioxide concentration

* Risk of barotrauma with pneumomediastinum, pneumothorax, and subcutaneous emphysema

Miller, 2010

Facilitating a smooth emergence

Tools for Induction:

Standard induction*

Laryngoscopes used:

1. Kleinasser

2. Dedo

3. Holinger

Figure 38-15

("Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

• Small VT values + low peak & mean airway pressures associated with subglottic HFJV enable patient to breathe spontaneously
• Increase frequency of ventilation to 300 breaths/min
• Increase FIO2 to 1.0
• Set ventilator driving pressure to 10 psi (this enables continuous flow of O2 and apnea oxygenation + rise in CO2
• IF obstruction > 50% jet nozzle should be proximal to site of obstruction to prevent barotrauma

Hunsaker Mon-Jet Ventilation tube:

• Laser resistant plastic
• Double lumen ETT
• One lumen for jet ventilation
• One lumen for gas sampling

Figure 38-4

("Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

(Sue, Li, & Liu, 2014)

("Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

(Sandberg & Ehrenfeld, 2011)

Induction sequence and status post:

Gas exchange details

Principal: Tidal volumes < dead space (anatomic + equipment)

Placement of the Hunsaker via Dedo laryngoscopy

Must occur alternative means + standard block flow (convective) ventilation that occurs during normal inspiratory-expiratory cycle where gas is delivered directly to alveoli (HFJV>LFJV)

Set up after for optimal exposure for surgeon:

Laminar flow (non-turbulent, low Reynolds number) in small airways, high pressure from delivered breath flows down middle of airway & margins of airway contain gas moving in opposite direction

Pedulluft effect movement of inspired gas from alveoli that fill fastest to those that are slower to fill. Based on variability between alveoli in both resistance and compliance

Taylor dispersion (convective streaming) diffusion of high velocity central gases to margins of airway. Occurs in smaller airways & further enhances gas mixing and hence exchange

Cardiogenic mixing contributes to gas exchange, occurs as a result of rhythmic, pulsatile nature of heart conferring a mixing of gases

Figure 3 Hyperpolarized He-MRI of gas distribution

(Simon, Kaczka, Bankier, & Parraga, 2012)

(Figure 38-4 "Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

("OpenAnesthesia," 2012)

Figure 38-5 ("Anesthetic and Airway Management of Microlaryngeal Surgery and Upper Airway Endoscopy," 2015)

Mechanics of ventilation:

Different means of gas exchange

Role:

We control the respirations with the O2 control button

Periodically the surgeon will request to hold ventilation

This requires clear and concise communication between the surgeon and the anesthesia provider

HFJV:

* High pressure

* Low volume breaths

* ICU setting

LFJV:

* Manually triggered hand-held device

* During short procedures (rigid bronchoscopy)

* Airway surgery

* After cricothyrotomy

Figure 3-3

(Themes, 2016)

Miller 2010